Electrolyzer Having Increased Contact Specific Surface Area for the Recovery of Valuable Metals

ABSTRACT

The present invention includes an electrolyzer having increased contact specific surface area for the recovery of valuable metals comprising a housing having a rear end with an inlet port, a front end with an outlet port, an internal space with a downwardly inclined bottom, a plurality of anodes arranged to divide the internal space in a widthwise direction, and a plurality of cathode units arranged to divide each space between adjacent anodes into two electrolytic spaces. Wastewater is introduced through the inlet port, sequentially passes through the electrolytic spaces, and is discharged through the outlet port such that valuable metals are recovered on the cathode units. Each of the cathode units has a first, second, and third cathode and cathode wires which fill the spaces among the first, third and second cathodes to increase the contact specific surface area of the wastewater introduced into the electrolyzer.

CLAIM TO FOREIGN PRIORITY

The present application is a U.S. National Stage Application filed under 35 U.S.C. 371 claiming priority from International Application No. PCT/KR2010/006937, filed Oct. 11, 2010, which claims the benefit of priority of Korean Application No. 10-2009-0097231, filed Oct. 13, 2009.

FIELD OF THE INVENTION

The present invention relates to an electrolyzer having an increased contact surface area for recovery of valuable metals which has an increased electrolytic efficiency obtained by maximally increasing the specific surface areas of electrodes where wastewater to be electrolyzed comes in contact, and which allows valuable metals to be effectively electro-deposited and recovered even from low-concentration wastewater.

BACKGROUND OF THE INVENTION

In general, a large amount of heavy metals are contained in wastewater generated when valuable metals are recovered for recycling from electronic part scraps including printed circuit boards used for various electronic products or from waste catalysts usually generated in chemical factories, in wastewater from a plating mill, a textile mill, or other mills, and in wastewater generated when a photograph is developed. An important pending question to address concerns creating value from waste resources, preventing environmental pollution by recycling the wastewater, and effectively recovering valuable metals that are worth recovering from the wastewater.

In one method of recovering valuable metals, such as platinum (Pt), palladium (Pd), rhodium (Rh), gold (Au), silver (Ag), and copper (Cu), which includes processing wastewater containing valuable metals, waste resources are crushed and valuable metals are leached from the crushed waste resources with a solvent, which is usually acid or alkali, and then chemical deposition or electrolysis is used to recover the valuable metals.

In addition to recovering valuable metals or heavy metals contained in wastewater, the electrolysis method is used for processing and producing common inorganic compounds or organic compounds, but has disadvantages because it takes a long time to perform the processes with the existing electrolysis apparatuses, the efficiency is low, and the apparatuses occupy large spaces.

Meanwhile, a processing method that makes wastewater sludge by performing chemical treatment and settling the sludge is generally used as a wastewater processing method and is currently commonly used in plating mills. The method causes severe environmental pollution by discharging valuable metal components contained in wastewater and the used water without recycling the metal components or the used water, and a large expenditure is necessary for the chemical treatment.

FIG. 1 shows an embodiment of electrolyzer 100 in the related art that electro-deposits and recovers valuable metals from plating-wastewater or other wastewater containing valuable metals, in which cylindrical inner electrode plate 130 and cylindrical outer electrode plate 120 are disposed in cylindrical housing 110 with an internal space. Housing 110 has inlet port 112 through which wastewater is introduced and outlet port 111.

Using this structure, power is supplied from an external power source (not shown) and electricity flows to inner electrode 130 and outer electrodes 120. Inner electrode 130 and outer electrode 120 may be arbitrarily assigned a polarity, in which one of them has a negative polarity and the other has a positive polarity.

Therefore, the cathode is supplied with electrons from the power source and an electrochemical reduction reaction is generated in wastewater in the electrolyzer, in which positive ions are diffused to an electrode surface and reduced by receiving the electrons, so that valuable metals adhere to the cathode and are recovered.

However, in the electrolyzer 100 of the related art which has one cathode and one anode, the specific surface area of the cathode is not large. As a result the area and time in which the wastewater in the electrolyzer comes in contact with the cathode are small, which is a factor that prevents effective recovery of the valuable metals.

Further, for low-concentration wastewater, that is, wastewater containing valuable metals of 10 ppm or less, the contact specific surface area is very small. As a result the electro-deposition and recovery of the valuable metals are difficult, and accordingly, the efficiency is very low.

In other words, since the reduction is generated only on the surface of one cathode, the reaction speed is limited and a plurality of electrolyzers 100 is necessary for mass production. Also, the electrolysis efficiency largely decreases as time passes.

An electrode plate made of titanium (Ti) is generally used for an electrode, which has the advantage that titanium is not dissolved by the nitrohydrochloric acid used for recovering the electro-deposited valuable metals. However, because the electric conductivity of titanium is low, for use the surface is plated with metals or combinations of metals having high electric conductivity.

Therefore, it is required to develop an electrolyzer having a structure that makes it possible to increase electrolysis efficiency for recovering valuable metals while having a structure with a large specific surface area that comes in contact with wastewater.

SUMMARY OF THE INVENTION

The present invention was developed in order to solve the problems discussed above. An object of the present invention is to provide an electrolyzer having increased contact specific surface area for the recovery of valuable metals, the electrolyzer including a housing having a rear end with an inlet port, a front end with an outlet port, and an internal space with a downwardly inclined bottom. The electrolyzer further includes a plurality of anodes arranged within the housing such that each of the anodes divides the internal space of the housing in a widthwise direction and a plurality of cathode units interposed between the anodes to divide the space between adjacent anodes into two electrolytic spaces. Wastewater introduced through the inlet port sequentially passes through the plurality of electrolytic spaces such that valuable metals are electro-deposited to the cathode units and recovered.

In order to achieve the object of the present invention, an electrolyzer having increased contact specific surface area for the recovery of valuable metals includes a housing having a rear end with an inlet port, a front end with an outlet port, and an internal space with a downwardly inclined bottom. The electrolyzer further includes a plurality of anodes arranged within the housing such that each of the anodes divides the internal space of the housing in a widthwise direction and a plurality of cathode units interposed between the anodes to divide the space between adjacent anodes into two electrolytic spaces. Wastewater introduced through the inlet port sequentially passes through the plurality of electrolytic spaces such that valuable metals are electro-deposited to the cathode units and recovered.

Each of the cathode units in an embodiment of the present invention is formed in a plate structure dividing the internal space of the housing in the width direction. Cathode units are inserted into the housing by sliding both sides of the cathode unit on the inner surface of the housing. An overflow channel gap is defined above the cathode to allow wastewater to overflow.

Each of the cathode units includes a first cathode that is disposed between the anodes such that the space between adjacent anodes is divided into two electrolytic spaces. The first cathode is formed in a plate structure dividing the internal space of the housing in the width direction, and defines overflow channel space d that allows wastewater to overflow through the space above cathode unit 30. Each cathode unit further includes a second cathode formed in a plate shape having a net structure at a predetermined distance from one side of the first cathode, a third cathode formed in a plate shape having a net structure at a predetermined distance from the other side of the first cathode, and cathode wires formed in a lump structure with an increased specific surface area that comes in contact with wastewater. The cathode wires fill a space defined by the first and second cathode and a space defined by the first and third cathode. The valuable metals are electro-deposited and recovered on the cathode units having the cathode wires while wastewater introduced through the inlet port sequentially passes through the electrolytic spaces.

The cathode wires are disposed in close contact with each other in a coil spring shape.

The cathode wires have a pot scourer structure formed by gathering adjacent cathode wires.

Each of the anodes of the present invention is disposed between adjacent cathode units or disposed between the inner wall of the front or rear end of the housing and a cathode unit. Each anode is formed in a plate structure dividing the internal space of the housing in the width direction, is inserted in the housing by sliding both sides on the inner surfaces of the housing, and has a lower end that defines a wastewater discharge channel gap.

The housing includes an external body that has a shape with upper and lower portions open, an inlet port communicating with the outside in an upper portion of the rear end, and an outlet port at the upper portion of the front end, a lower cap that is joined with the lower portion of the external body and forms the bottom of the housing, and an upper cap that is joined with an upper portion of external body 10 a to form the top of the housing and has one or more gas exhaust holes.

The external body further includes a plurality of first drain valves that communicate with the upper portion of the electrolytic space at an upper portion of a side wall.

The lower cap further includes a plurality of second drain valves that communicate with lower portions of the electrolytic spaces.

The housing further includes fluid blocking balls in the internal space which allow gas to freely move and prevent wastewater from leaking by closing the gas exhaust hole in accordance with the internal pressure. The upper cap further includes ball-retaining net fences formed in net structures to control free movement of the fluid blocking balls in the internal space of the housing by supporting the fluid blocking balls.

The anodes and the cathodes of the cathode units are made of unplated titanium (Ti).

According to an electrolyzer having an increased contact specific surface area for recovery of valuable metals, first it is possible to increase the contact specific surface area of wastewater introduced in the electrolyzer by using cathode units each including a first, second, and third cathode and cathode wires filling the spaces between the cathodes, such that it is possible to easily electro-deposit and recover the valuable metals even from wastewater containing a small amount of valuable metals.

Second it is possible to achieve high electrolysis efficiency because the cathode units are disposed between the anodes and a plurality of electrolytic spaces is defined, such that valuable metals are electro-deposited while wastewater sequentially passes through the electrolytic spaces.

Third, it is possible to increase stability of the electrolyzer because gas generated in the electrolysis process is discharged first by gas exhaust holes formed in the top of the housing, and wastewater is prevented from leaking by using fluid blocking balls that close the gas exhaust holes according to the internal pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing an electrolyzer for recovering valuable metals according to the related art.

FIG. 2 is a side cross-sectional view showing an embodiment of an electrolyzer having an increased contact specific surface area for recovering valuable metals according to the present invention.

FIG. 3 is a side cross-sectional view showing an embodiment of an electrolyzer having an increased contact specific surface area for recovering valuable metals according to the present invention.

FIG. 4 is a side cross-sectional view showing another embodiment of an electrolyzer having an increased contact specific surface area for recovering valuable metals according to the present invention.

FIG. 5 is a plan view showing another embodiment of an electrolyzer having an increased contact specific surface area for recovering valuable metals according to the present invention.

FIGS. 6 a and 6 b are views showing embodiments of a cathode wire that is applied to an electrolyzer having an increased contact specific surface area for recovering valuable metals according to the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Hereinafter, preferred embodiments of the present invention are described with reference to the accompanying drawings such that those skilled in the art can easily implement the present invention.

FIG. 2 is a side cross-sectional view showing an embodiment of an electrolyzer having an increased contact specific surface area for recovering valuable metals according to the present invention. FIG. 3 is a side cross-sectional view showing an embodiment of an electrolyzer having an increased contact specific surface area for recovering valuable metals according to the present invention. FIG. 4 is a side cross-sectional view showing an electrolyzer having an increased contact specific surface area for recovering valuable metals according to the present invention. FIG. 5 is a plan view showing an electrolyzer having an increased contact specific surface area for recovering valuable metals according to the present invention. The present invention is described hereafter with reference to FIGS. 2-5.

The present invention relates to an electrolyzer that has anode and cathode electrodes and recovers valuable metals in wastewater by electro-depositing using electrolysis. The electrolyzer includes a housing having a rear end with an inlet port, a front end with an outlet port, and an internal space with a downwardly inclined bottom. The electrolyzer further includes a plurality of anodes arranged within the housing such that each of the anodes divides the internal space of the housing in a widthwise direction and a plurality of cathode units interposed between the anodes to divide the space between adjacent anodes into two electrolytic spaces.

Wastewater introduced through the inlet port sequentially passes through the plurality of electrolytic spaces such that valuable metals are electro-deposited to the cathode units and recovered.

The housing of the present invention may further have gas exhaust holes through the top. Accordingly, gas is discharged through the gas exhaust hole and discharged to the outside through the outlet port.

As shown in the figures, electrolyzer 1 having an increased contact specific surface area for recovering valuable metals according to the present invention is configured to increase electrolysis efficiency by maximally increasing the specific surface areas of the electrodes that wastewater introduced into electrolyzer 1 comes in contact with such that valuable metals, which can be recycled from plating-wastewater or wastewater containing valuable metals, can be efficiently electro-deposited and recovered. The electrolyzer is further configured to efficiently electro-deposit and recover valuable metals even from wastewater containing a small amount of valuable metals by increasing the electrolytic space.

For this configuration, electrolyzer 1 for recovering valuable metals according to the present invention includes a plurality of anodes 20 disposed at predetermined distances in a housing and cathode units 30 disposed between two adjacent anodes 20 to form electrolytic spaces together with the anodes and where valuable metals are electro-deposited, as power is supplied, in order to electro-deposit the valuable metals in wastewater by using electrolysis with anode and cathode electrodes.

The housing 10 has an internal space defined by inlet port 11 through which wastewater is introduced at the rear end, outlet port 12 at the front end, and gas exhaust holes 13 at the top and which provides a space where the wastewater is electrolyzed. Preferably, inlet port 11 may be formed through an upper surface of the rear end of housing 10, outlet port 12 may be formed in an upper portion of the front end, and gas exhaust holes 13 may be formed through the top of housing 10.

Cathode units 30 each divide each of the spaces between the anodes and cathodes into two electrolytic spaces A.

Anodes 20 are disposed in the internal space of housing 10 and divide the internal space in the width direction.

Electrolyzer 1 for recovering valuable metals is configured to allow valuable metals in wastewater introduced through the inlet port of the housing to be recovered by being electro-deposited to cathode units 30 while the wastewater sequentially passes through electrolytic spaces A.

Gas generated in the electro-deposition process, that is the electrolysis process in the electrolytic spaces, is discharged to the outside of housing 10 through gas exhaust holes 13.

Wastewater with the valuable metals recovered is discharged to the outside through outlet port 12 of housing 10.

Gas exhaust holes 13 are provided to discharge first the gas generated in the electrolysis process in housing 10 that fails to come out of the internal space of housing 10 and remains therein while the wastewater passes through electrolytic spaces A.

This is necessary in order to prevent damage to electrolyzer 1 and the possibility of an accident due to the gas remaining in the internal space.

Anodes 20 and cathode units 30 are connected to an external power source (not shown) through electrode tips protruding outward from housing 10, as in the technology that is commonly known in the art, and supplied with power, and show a positive charge and a negative charge, respectively. Preferably, housing 10 with protruding electrode tips has a structure that prevents wastewater from leaking outside.

In the embodiments shown in the figures, housing 10 may be formed in a box shape having an internal space and declining from the upper portion of the rear end to the lower portion of the front end.

In this case, anodes 20 and cathode units 30 may be formed in plate shapes that divide the internal space of housing 10 in the width direction.

As shown in FIGS. 2 and 3, each of cathode units 30 in an embodiment of the present invention is formed in a plate structure dividing the internal space of housing 10 in the width direction and are inserted into housing 10 by sliding both sides on the inner surface of housing 10. Overflow channel gap d is defined above cathode 30 to allow wastewater to overflow.

As shown in the figures, when the cathodes are formed in plate structures, it has the advantage of being able to recover valuable metals, such as nickel (Ni), copper (Cu), or iron (Fe), from high-concentration wastewater.

According to electrolyzer 1 for recovering valuable metals having the configuration of the invention, valuable metals in wastewater are electro-deposited to cathode units 30 and recovered while the wastewater introduced through the inlet port of housing 10 sequentially passes through electrolytic spaces A.

Cathode units 30 may be fixed with the lower ends seated in seating grooves 72 formed on the bottom of housing 10, that is, the inner surface of lower cap 10 c, such that wastewater introduced in the internal space can overflow and flow into adjacent electrolytic spaces through portions above cathode units 30.

It is preferable that an upper portion of cathode unit 30 defines overflow channel gap d together with a bottom of upper cap 10 b to guide wastewater to be able to easily overflow above cathode unit 30. For this configuration, it is preferable that both sides of cathode unit 30 be in close contact with both inner surfaces of the housing to prevent wastewater from flowing into the next electrolytic space through both sides of cathode unit 30.

That is, cathode unit 30 may be disposed in housing 10 by sliding both sides into housing 10, the sides of the cathode unit sliding on both sides of housing 10, and seating the lower end of the cathode unit into seating groove 72.

Electrolyzer 1 having an increased contact specific surface area for recovering valuable metals according to an embodiment of the present invention increases the ratio of recovery of valuable metals by repeating the electrolysis process of wastewater several times by defining a plurality of electrolytic spaces by disposing cathode units 30 between anodes 20.

The wastewater overflows above cathode unit 30 and flows into a next electrolytic space A and flows through a portion under anode 20 into a next electrolytic space A, such that it sequentially passes through the inside of housing 10.

In another embodiment of an electrolyzer 1 having an increased contact specific surface area for recovering valuable metals of the present invention, shown in FIGS. 4 and 5, each of cathode units 30 where valuable metals in wastewater are practically electro-deposited and recovered in an electrolysis process includes first cathode 31 that is disposed between anodes 20 such that a space between adjacent anodes 20 is partitioned into two electrolytic spaces. First cathode 31 is formed in a plate structure dividing the internal space of housing 10 in the width direction and defines overflow channel space d that allows wastewater to overflow through the space above cathode unit 30. Each of cathode units 30 further includes second cathode 32 that is formed in a plate shape having a net structure at a predetermined distance from one side of first cathode 31, third cathode 33 that is formed in a plate shape having a net structure at a predetermined distance from the other side of the first cathode, and cathode wires 34 that are formed in a lump structure with an increased specific surface area that comes in contact with wastewater and that fill a space defined by the first and second cathode and a space defined by the first and third cathode.

Next, valuable metals are electro-deposited and recovered on cathode units 30 having cathode wires 34 while wastewater introduced through inlet port 11 sequentially passes through electrolytic spaces A.

Cathode wires 34 are formed in a lump at a side in the electrolytic space. It is preferable to dispose cathode 31 having a plate structure between the two cathodes 32 and 33 having net structures and dispose the cathode wire in a lump in spaces a defined by cathode 31 having a plate structure and cathodes 32 and 33 having net structures in order to increase the contact specific surface area of wastewater through the cathode wires.

According to electrolyzer 1 for recovering valuable metals having the configuration of the invention, the valuable metals in wastewater are electro-deposited on cathode units 30 including the lump of cathode wires 34 and recovered while the wastewater introduced through inlet port 11 of housing 10 sequentially passes through electrolytic spaces A.

In this configuration, it is preferable that the bottom of cathode unit 30 is blocked by a net structure of a plate structure such that cathode wires 34 filling space a are not separated when being attached/detached in the electrolyzer 1, if necessary.

Cathode units 30 may be fixed with lower ends seated in seating grooves 72 formed on the bottom of housing 10, that is, an inner surface of lower cap 10 c, such that wastewater introduced in the internal space can overflow and flow into the adjacent electrolytic spaces through the portions above first cathodes 31.

It is preferable that the upper portion of first cathode 31 defines overflow channel gap d together with the bottom of upper cap 10 b to guide wastewater to be able to easily overflow above first cathode 31. For this configuration, it is preferable that both sides of cathode unit 30 be in close contact with both inner surfaces of the housing to prevent wastewater from flowing into the next electrolytic space through both sides of cathode unit 30.

That is, cathode unit 30 may be disposed in housing 10 by sliding both sides into housing 10, the sides of the cathode unit sliding on both sides of housing 10, and seating the lower end of the cathode unit into seating groove 72.

Electrolyzer 1 having an increased contact specific surface area for recovering valuable metals according to an embodiment of the present invention increases the contact specific surface area by filling wires 34 in spaces a between cathodes having a net structure of a plate structure, and increases the ratio of recovery of valuable metals by repeating the electrolysis process of wastewater several times by defining a plurality of electrolytic spaces by disposing cathode units 30 between anodes 20.

For this configuration, a plurality of cathode wires is disposed in close contact with each other in a coil spring shape.

For example, FIG. 6 shows cathode wire 34 filled and positioned in one space a of electrolytic space A by second electrode 32 and third electrode 33 of cathode unit 30.

The cathode wires have a pot scourer structure formed by gathering with adjacent cathode wires.

As shown in the figure, the structure of filled cathode wires 34 maximally increases the specific surface area of cathode unit 30 and increases the amount of valuable metals electro-deposited from wastewater, such that it is possible to increase the entire electrolysis efficiency and the ratio of valuable metals.

In other words, cathode wires 34 may be filled in a coil spring or in a pot scourer structure by gathering with adjacent cathode wires 34, so as to be easily attached/detached in spaces a and to increase the specific surface area.

Wastewater overflows above first cathodes 31 and flows into a next electrolytic space A and flows through the portion under anode 20 into a next electrolytic space A, such that the wastewater sequentially passes through the inside of housing 10.

In the embodiments of the present invention, seating grooves 72, as shown in the figures, may be formed on the tops of fixing portions 70 formed on the bottom in the internal space of housing 10.

It is preferable that a lower end of cathode unit 30 be seated in seating groove 72 and be easily attached/detached to/from seating groove 72 in order to easily replace cathode unit 30.

In the embodiments of the present invention, each of anodes 20 of the present invention is disposed between adjacent cathode units 30 or disposed between the inner wall of the front or rear end of housing 10 and a cathode unit 30. Each of anodes 20 is formed in a plate structure dividing the internal space of housing 10 in the width direction, is inserted into housing 10 by sliding both sides on the inner surfaces of housing 10, and has a lower end that defines wastewater discharge channel gap c.

It is preferable that the upper end of each of anodes 20 be in close contact with the bottom of upper cap 10 b to prevent exhaust gas collecting in an upper portion from infiltrating into the adjacent housing space. That is, this is for preventing exhaust gas collecting at a portion above cathode unit 30 between two adjacent anodes 20 from infiltrating into a portion above another cathode unit 30.

As shown in the figure, as cathode unit 30 is disposed in the space defined by two adjacent anodes 20, cathode unit 30 defines electrolytic spaces A together with anodes 20.

Two adjacent electrolytic spaces are connected by an S-shaped channel, such that valuable metals are electro-deposited and recovered on cathode units 30 while wastewater introduced through inlet port 11 sequentially passes through electrolytic spaces A, and then the wastewater is discharged outside through outlet port 12.

In the embodiments of the present invention, housing 10 includes external body 10 a that has a shape with upper and lower portions open, has inlet port 11 communicating with the outside at an upper portion of the rear end, and has outlet port 12 at an upper portion of the front end, lower cap 10 c that is combined with the lower portion of external body 10 a and forms a bottom of housing 10, and upper cap 10 b that is combined with the upper portion of external body 10 a to form a top of the housing and has one or more gas exhaust holes 13.

Lower cap 10 c forms the bottom of housing 10 by being fastened to the lower portion of external body 10 a by fasteners, such as bolts.

Upper cap 10 b forms the top of housing 10 by being fastened to the upper portion of external body 10 a by fasteners, such as bolts, and has gas exhaust holes 13 formed through upper cap 10 b at predetermined positions.

Inlet port 11 is connected with external inlet pipe 40 through which wastewater flows from the outside. In addition, external pump P that forcibly introduces wastewater into housing 10 may be disposed at one side of external inlet pipe 40.

Inlet channel 10 a-1 defined by a rear end wall of external body 10 a and adjacent anode 20 communicates with inlet port 11. Wastewater introduced into inlet channel 10 a-1 can flow into an adjacent electrolytic space through a portion under a lower end of anode 20.

External inlet pipe 40 may further include additive inlet pipe 50 at one side of external inlet pipe 40 for forcibly injecting a current density additive for increasing electric conductivity.

In this configuration, a control valve (not shown) is further disposed in additive inlet pipe 50 to control the inflow and the amount of inflow of the current density additive, which is injected manually or automatically, by controlling the control valve in accordance with the manual or automatic injection.

Outlet channel 10 a-2 defined by a front end wall of external body 10 a and adjacent anode 20 communicates with outlet port 12. Wastewater passing through a portion under anode 20 in an electrolytic space adjacent to outlet channel 10 a-2 flows into outlet channel 10 a-2 and can be discharged outside through outlet port 12.

External body 10 a further includes a plurality of first drain valves 60 that communicate with an upper portion of the electrolytic space at an upper portion of a side wall.

As shown in the figure, each of first drain valves 60 prevents wastewater from overflowing to a portion above the cathode unit when first drain valve 60 is open while communicating with an upper portion of electrolytic space A, such that it is possible to completely remove the wastewater in the next electrolytic space. Further, first drain valve 60 makes it easy to replace the anode or cathode unit by preventing wastewater from overflowing to the next electrolytic space.

Further, first drain valves 60 may be arranged in a first line in the longitudinal direction of a side wall of external body 10 a, in which first drain valves 60 arranged in a line may be connected to communicate with each other by drain pipe 62.

It is possible to control the flow of wastewater between electrolytic spaces, which are not adjacent to each other, by using first drain valves 60. For example, it is possible to allow the wastewater to flow from an electrolytic space at the inlet portion to an electrolytic space at the outlet port.

Further, external body 10 a may further include first drain valves 60 arranged in a second line, parallel with the first line of the first drain valves 60, in the longitudinal direction of the side wall of external body 10 a. In this configuration, first drain valves 60 in the second line may be connected to communicate with drain pipe 64.

First drain valves 60 connected to communicate with each other by drain pipe 64, as described above, perform the same function as first drain valves 60 connected by drain pipe 62.

It is preferable to connect drain pipe 62 with drain pipe 64 such that they are communicate with each other, in order to more efficiently discharge wastewater to the outside through an upper portion of the side wall of external body 10 a.

Lower cap 10 c further includes a plurality of second drain valves 66 that communicates with lower portions of the electrolytic spaces.

As shown in the figure, second drain valves 66 allow lower portions of the electrolytic spaces to communicate with the outside at lower cap 10 c.

In this case, it is preferable that second drain valves 66 communicate with lower portions of electrolytic spaces A adjacent to rear ends of fixing portions 70 formed on the top of lower cap 10 c. Since housing 10 generally inclines, wastewater may collect around the rear ends of fixing portions 70, such that it is necessary to position second drain valves 66 at rear ends of fixing portion 70 in order to completely remove wastewater from housing 10.

Further, housing 10 further includes fluid blocking balls 14 in the internal space which allow gas to freely move and prevent wastewater from leaking by closing gas exhaust hole 13 in accordance with an internal pressure. Upper cap 10 b further includes ball-retaining net fences 15 that are formed in net structures to control free movement of fluid blocking balls 14 in the internal space of housing 10 by supporting fluid blocking balls 14.

Fluid blocking balls 14 can allow gas to be freely moved and discharged and prevent wastewater in the internal space from leaking by closing gas exhaust holes 13 in accordance with the internal pressure of the internal space during an electrolysis process.

Gas exhaust holes 13 are formed through upper cap 10 b, and ball-retaining net fences 15 support the fluid blocking balls 14 on an inner surface of upper cap 10 b such that free movement of fluid blocking balls 14 in the internal space of housing 10 is controlled.

That is, fluid blocking balls 14 disposed around gas exhaust holes 13 are moved to close gas exhaust holes 13 by ball-retaining net fences 15 in accordance with the internal pressure, thereby preventing wastewater from leaking.

The anodes and the cathodes of the cathode units are made of unplated titanium (Ti).

The electrodes of anodes 20 and cathode units 30 that are applied to electrolyzer 1 for recovering valuable metals of the present invention are preferably made of titanium (Ti). The titanium makes it possible to achieve high-purity valuable metals without creating impurities when the valuable metals are extracted by nitrohydrochloric acid in the next process.

Hereafter the process of recovering valuable metals, that is, the electrolysis process of electrolyzer 1 having an increased contact surface area for recovery of valuable metals according to another embodiment of the present invention, is described.

First, wastewater containing valuable metals is introduced into the internal space of housing 10 by a pumping force provided by external pump P along external inlet pipe 40.

That is, the wastewater is introduced into inlet channel 10 a-1 through inlet port 11 of external body 10 a.

Next, the wastewater introduced in the electrolytic space flows to the next electrolytic space while overflowing through an S-shaped channel above first cathode 31.

Next, the wastewater flows into the next electrolytic space A through lower wastewater outlet channel gap c under anode 20.

By repeating these processes, the wastewater is finally discharged outside through outlet port 12.

Cathode wires 34 are filled and positioned in a lump in space a defined by second cathode 32 and first cathode 31 of cathode unit 30 and space a defined by third cathode 33 and first cathode 31.

In this configuration, second cathode 32 and third cathode 33 are cathodes having a net structure, such that wastewater comes in contact with the surface of cathode wires 34 through the net structures.

When power is supplied to electrode tips protruding outside from the housing, charge moves to cathode units 30 and anodes 20, such that the valuable metals in wastewater are electro-deposited and recovered on cathode units 30, and specifically, on the lump of cathode wires 34 with the largest specific surface area.

When the housing is fully filled with wastewater due to non-smooth discharge of the wastewater through outlet port 12 when the wastewater is introduced into housing 10 through inlet port 11, the wastewater stably passes through the electrolytic spaces without leaking through gas exhaust holes 13 because of fluid blocking balls 14.

Gas generated in the electrolysis process is discharged outside through gas exhaust holes 13, such that it is possible to improve stability of electrolyzer 1.

If necessary, it is possible to increase the ratio of recovery of valuable metals by controlling the control valve (not shown) of additive inlet pipe 50 such that a predetermined amount of a current density additive is introduced into the internal space of housing 10.

Therefore, it is possible to discharge wastewater containing valuable metals at a concentration of 0.5 to 2 ppm through the outlet port when processing wastewater containing valuable metals at a concentration of 50 ppm.

Although the present invention is described above with reference to preferred embodiments, the present invention is not limited to the embodiments shown and should be construed on the basis of the claims. Further, the present invention may be changed and modified in various ways by those skilled in the art without departing from a range equivalent to the claims and the spirit of the present invention.

The present invention provides an electrolyzer having an increased contact specific surface area for recovery of valuable metals and makes it possible to increase the contact specific surface area of wastewater introduced in the electrolyzer by using cathode units each including a first, second and third cathodes and cathode wires filling the spaces between the cathodes. The present invention also makes it possible to easily electro-deposit and recover valuable metals even from wastewater containing a small amount of valuable metals and to achieve high electrolysis efficiency because the cathode units are disposed between the anodes to define a plurality of electrolytic spaces, such that valuable metals are electro-deposited while wastewater sequentially passes the electrolytic spaces. The present invention also increases the stability of the electrolyzer because gas generated in the electrolysis process is discharged first by gas exhaust holes formed in the top of the housing, and prevents wastewater from leaking by using fluid blocking balls that close the gas exhaust holes according to the internal pressure if necessary. Therefore, the present invention has industrial applicability. 

1. An electrolyzer having increased contact specific surface area for the recovery of valuable metals, which has anodes and cathodes and recovers valuable metals by electro-depositing the valuable metals from wastewater by using electrolysis, the electrolyzer comprising: a housing having a rear end with an inlet port, a front end with an outlet port, and an internal space with a downwardly inclined bottom; a plurality of anodes arranged within the housing such that each of the anodes divides the internal space of the housing in a widthwise direction; and a plurality of cathode units interposed between the anodes to divide spaces between adjacent anodes into two electrolytic spaces, wherein the wastewater introduced through the inlet port sequentially passes through the plurality of electrolytic spaces and is discharged through the outlet port, such that valuable metals are electro-deposited on the cathode units, wherein each of the cathode units includes, (a) a first cathode disposed between the anodes such that the space between adjacent anodes is divided into two electrolytic spaces, formed in a plate structure dividing the internal space of the housing in a width direction, and that forms an overflow channel gap that allows wastewater to overflow through a space above the cathode unit, (b) a second cathode that is formed in a plate shape having a net structure at a predetermined distance from a first side of the first cathode, (c) a third cathode that is formed in a plate shape having a net structure at a predetermined distance from a second side of the first cathode opposite the first side of the first cathode, and (d) cathode wires that are formed in a lump structure with an increase specific surface area that comes in contact with wastewater and that fill a first space formed by the second cathode and first cathode and a second space formed by the third cathode and first cathode, wherein the valuable metals are electro-deposited and recovered to the cathode units having the cathode wires while wastewater introduced through the inlet port sequentially passes through the electrolytic spaces.
 2. The electrolyzer according to claim 1, wherein each of the cathode units is formed in a plate structure dividing the internal space of the housing in the width direction, is inserted into the housing by sliding first and second sides of the cathode unit on inner surfaces of the housing, and an overflow channel gap is formed above each of the cathode units to allow wastewater to overflow.
 3. The electrolyzer according to claim 1, wherein the cathode wires are disposed in close contact and have a coil spring shape.
 4. The electrolyzer according to claim 1, wherein the cathode wires have a pot scourer structure formed by gathering together adjacent cathode wires.
 5. The electrolyzer according to claim 1, wherein each of the anodes is disposed between adjacent cathode units or disposed between the inner wall of the front end or rear end of the housing and the cathode unit, is formed in a plate structure dividing the internal space of the housing in the width direction, is inserted in the housing by sliding first and second sides of the anode on inner surfaces of the housing, and has a lower end that forms a wastewater discharge channel gap.
 6. The electrolyzer according to claim 1, wherein the housing further includes: an external body that has a shape with upper and lower portions open, has the inlet port communicating with the outside at an upper portion of the rear end, and has the outlet port at an upper portion of the front end; a lower cap that is combined with the lower portion of the external body and forms the downwardly inclined bottom of the housing; and an upper cap that is combined with the upper portion of the external body to form a top of the housing and has one or more gas exhaust holes.
 7. The electrolyzer according to claim 6, wherein the external body further includes a plurality of first drain valves that communicates with an upper portion of the electrolytic spaces at an upper portion of a side wall.
 8. The electrolyzer according to claim 6, wherein the lower cap further includes a plurality of second drain valves that communicate with lower portions of the electrolytic spaces.
 9. The electrolyzer according to claim 6, wherein the housing further includes fluid blocking balls in the internal space which allow a gas to freely move and prevent wastewater from leaking by closing the gas exhaust hole in accordance with an internal pressure, and the upper cap further includes ball-retaining net fences that are formed in net structures to control free movement of the fluid blocking balls in the internal space of the housing by supporting the fluid blocking balls.
 10. The electrolyzer according to claim 1, wherein the anodes and the cathodes of the cathode units are made of unplated titanium. 